No-dig CIPP patch · 50-year design life · WRC report
Patch Repair Drain London
Localised CIPP patch repair for isolated drain defects — displaced joints, cracks, root ingress points, small holes. 500mm–1.5m fibreglass patches installed via inflatable packer. Zero excavation, freeholder and insurance-accepted WRC report.
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Patch repair — the precise, low-cost no-dig fix for isolated drain defects
A localised CIPP patch repair is the correct method for any drain with one to three isolated defects and sound pipework in between. The patch is a short section of fibreglass sleeve (typically 500mm, 750mm, 1.0m, or 1.5m long) impregnated with epoxy or vinyl-ester resin and installed via an inflatable packer — pushed to the exact location of the defect through the existing manhole or rodding access, inflated to press the patch firmly against the pipe wall, cured in place. The result is a rigid new fibreglass sleeve inside the original pipe, spanning only the defective section, with a 50-year design life for the covered area.
The commercial case for patch repair versus full-length lining is precision. If the CCTV survey shows a single displaced joint at 4.2m from the manhole with sound pipework on either side, installing a 500mm patch across just that joint costs £1,150–£1,650. Lining the whole 12m run for the same defect costs £3,250–£4,850 and takes longer. Where the drain has multiple defects — three joints failed at 3m, 5.5m, 8m — three patches installed in a single visit (£2,950–£4,850) still typically beats a full-length liner in cost and disruption. The tipping point is roughly four defects: at five or more, or with any general wear along the run, the full-length liner is usually the more economic answer.
The pre-repair CCTV survey is what makes the patch approach viable. The survey defines the exact distance from the access point, the orientation of the defect on the pipe circumference (crown, invert, or side), the pipe diameter, and any adjacent lateral connections. Without that precision the patch is placed by guesswork and often misses the defect or covers the wrong area. Every patch job we quote is preceded by a WRC-format CCTV survey — the survey cost is included in the patch job pricing if the customer proceeds with the patch install.
Every patch repair we install is delivered by an engineer trained in CIPP installation to industry standard, with Water Regulations 1999 competency (WaterSafe registration, UK Certification Ltd certificate 136356 issued 8 September 2025, expiry 18 August 2030). Public liability £5,000,000 via SiriusPoint through Eaton Gate MGU, policy BE26ACTT000000018221, period 07/05/2026 to 06/05/2027. WRC-format post-repair report supplied as standard — accepted by freeholders, insurance loss adjusters, HMO licensing teams, and Thames Water without follow-up questions.
Six common patch repair applications
Single displaced joint
Classic Victorian clay drain defect — one ring-seal joint at a specific location has moved out of alignment (often at a settlement point) creating a gap where soil and roots enter. A single 500mm patch installed across the joint restores structural integrity without disturbing the rest of the drain.
Longitudinal crack in a specific section
A single-run crack, typically along the pipe crown, caused by ground settlement or historic mechanical damage. A 1.0–1.5m patch bridges the crack and restores load-bearing. Sound rest-of-drain does not need lining.
Root ingress at one lateral connection
Root ingress limited to a single T-junction where a lateral connects to the mainline. Robotic patch liner sized for the T-junction, installed via inflatable packer. Restores connection integrity.
Small hole or spalled area
A localised hole in the pipe wall (often at a corroded cast iron section, or a spalled clay area) up to about 30% of the pipe diameter. Patch liner bridges the hole and creates a new smooth surface without excavation.
Failed brick sewer localised repair
Older London brick barrel sewers with a spalled area, missing bricks, or a localised collapse. Custom-sized patch liner installed to restore the pipe cross-section without disturbing the surrounding brick.
Post-excavation verification patch
Following an excavation-repair of a mainline drain, a short patch liner over the connection point verifies the joint integrity and creates a smooth internal surface for CCTV verification.
The six-stage patch repair process
Every patch install we deliver follows the same disciplined sequence. Skipping the pre-repair CCTV is what turns a patch into a guess.
CCTV survey identifies the defect
The CCTV survey defines the exact location, extent, and character of the defect. Distance from manhole, orientation of defect (crown, invert, side), pipe diameter, and any adjacent connections. Without this precision, the patch is placed by guesswork and often misses.
Pipe cleared and prepped for patch
Pre-patch jetting to clear any deposits at the defect location. The pipe surface where the patch will bond needs to be clean of grease, silt, and loose material. Any active root ingress cleared with a mechanical cutter head.
Patch length and diameter selected
Fibreglass patch liner selected to match the pipe diameter (100mm, 150mm, 225mm etc.) and cut to length. Standard patch lengths 500mm, 750mm, 1.0m, 1.5m. Custom lengths on request. Impregnated with resin (typically ambient-cure epoxy or vinyl-ester) on site.
Patch positioned via inflatable packer
The resin-impregnated patch is wrapped around an inflatable packer (rubber bladder mounted on a push-rod) and pushed to the exact defect location — the CCTV camera on the packer confirms alignment. Packer inflated to press the patch firmly against the pipe wall.
Cure and packer withdrawal
Ambient-cure resin sets in 60–120 minutes (or 20–40 minutes with hot-water assistance) with the packer held in place. Once cured the packer is deflated and withdrawn. The patch is now a rigid fibreglass sleeve inside the original pipe, spanning the defect.
Post-cure CCTV verification and WRC report
Post-patch CCTV inspection verifies: patch correctly positioned over the defect, patch fully adhered to pipe wall (no wrinkles, no gaps), pipe internal diameter reduction within acceptable limits, hydraulic flow verified. Full WRC-format report supplied to customer, freeholder, and insurer as required.
Cost — patch repair drain
| Scope | Price (inc. VAT) | Includes |
|---|---|---|
| 500mm patch repair (isolated joint, crack, or ingress) | £1,150–£1,650 | Pre-repair CCTV, jetting prep, patch install, post-repair CCTV verification, WRC-format report |
| 1.0m patch repair (longer crack or multi-joint defect) | £1,350–£1,950 | As above with longer patch |
| 1.5m patch repair (extended defect) | £1,650–£2,350 | As above with 1.5m patch |
| Lateral T-junction patch (robotic install) | £1,450–£2,250 | Robotic T-junction patch install, connection verification, WRC report |
| Multiple patch repairs (single visit, up to 3 patches) | £2,950–£4,850 | Efficient multi-patch install where CCTV identifies several isolated defects on same drain run |
| Patch repair on brick sewer (custom size) | £1,850–£2,850 | Custom-sized patch for non-standard brick sewer profile, freeholder liaison included |
| Emergency same-day patch repair | +£150–£250 | Same-day dispatch and installation where the defect is causing active property damage |
Real London patch repair jobs
Islington Georgian terrace — single displaced joint patch
CCTV survey during a pre-purchase inspection found one displaced joint at 4.2m from manhole on a 12m mainline drain. Rest of drain sound. 500mm patch installed via inflatable packer, cure 90 minutes, post-CCTV verified. Total £1,395 including pre-CCTV and WRC report. Sale exchange completed on schedule with the repair certificate as evidence.
Chiswick Victorian terrace — cast iron mainline hole patch
Ground-floor bathroom smell traced to a small hole in the cast iron mainline drain at 1.8m from the WC connection, corroded through after 130 years of service. 1.0m patch installed, hole bridged, smell eliminated same day. Freeholder-format WRC report supplied. Total £1,650.
Battersea mansion block — three-patch multi-repair single visit
CCTV survey on a shared drain to the mainline identified three isolated defects: displaced joint at 3m, crack at 5.5m, root ingress at 8m T-junction. All three patched in a single visit — two 500mm patches on the joints, one 1.0m patch across the T-junction with robotic install. Freeholder-authorised, WRC report distributed to affected leaseholders. Total £3,850 for three patches versus £4,850+ for a full-length liner. Patch approach chosen because the rest of the drain was sound.
Patch repair drain across every London borough
Frequently asked questions
When is a patch repair the right answer versus a full-length liner?
How long does the patch installation and cure take?
Is a patch repair as durable as a full-length liner?
Can a patch repair be installed without an excavation?
What defects can a patch NOT repair?
Do you provide WRC-format reports for patch repair jobs?
What certification and insurance do you carry?
Can patches be installed on shared drains and party-wall drains?
How quickly can you attend for an urgent patch repair?
What if the patch reveals additional defects during CCTV verification?
Related services
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No-dig, 50-year design life. WRC-format report for freeholders and insurers included.
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